Spectroscopic characterization of cadion: UV–vis, resonance Raman and DFT calculations of a versatile metal complexing agent
Article first published online: 21 DEC 2012
Copyright © 2012 John Wiley & Sons, Ltd.
Journal of Raman Spectroscopy
Volume 44, Issue 4, pages 567–572, April 2013
How to Cite
Lepre, L. F., Inoue, F., Corio, P., Santos, P. S. and Ando, R. A. (2013), Spectroscopic characterization of cadion: UV–vis, resonance Raman and DFT calculations of a versatile metal complexing agent. J. Raman Spectrosc., 44: 567–572. doi: 10.1002/jrs.4228
- Issue published online: 10 APR 2013
- Article first published online: 21 DEC 2012
- Manuscript Accepted: 4 NOV 2012
- Manuscript Revised: 29 OCT 2012
- Manuscript Received: 31 AUG 2012
- heavy metals;
- charge transfer;
The spectroscopic characterization of cadion or 1-(4-nitrophenyl)-3-(4-phenylazophenyl)triazene, its anionic species and its complexes with Hg2+, Cd2+ and Ni2+ in DMSO solution is presented. Resonance Raman (RR) and UV–vis spectroscopy were the techniques of choice with results supported by density functional theory calculations. As previously reported, the UV–vis data indicate distinct absorption spectra for the five species mentioned, allowing for spectrophotometric metal differentiation. In order to understand the electronic spectra of such species, we performed a detailed RR investigation, where the spectral profiles revealed the vibrational modes mainly involved in the chromophoric moieties. The distinct enhancement profile observed for each species suggests that the charge transfer from the π-system to the electron withdrawing NO2 group is modulated by the electron donating triazene moiety, depending on the metal attached. The results reported herein show that RR spectroscopy can be potentially used in the metal detection of multicomponent samples by the proper choice of the excitation wavelength. Copyright © 2012 John Wiley & Sons, Ltd.